Billiards is a sport involving the use of a cue stick to hit a billiard ball on a generally planar surface. As used herein, billiards is a generic term used to refer to different types of cue sports including pool, snooker, English billiards, Caram billiards, or any other cue sport that involves hitting a billiard ball with a cue stick. Within each of these different types of billiard sports, there are various different games which specify rules for how the games are played. For example, in the billiard sport of pool, pool games include Eight Ball, Nine Ball, and Three-Ball.
Also, as used herein, a billiard ball refers to a spherical ball having a diameter in the range of 2.0 inches (50.8 mm) and 2.5 inches (63.5 mm) that is typically made of a crack/chip resistant plastic (such as a phenolic resin or a polyester). Governing bodies for different types of billiard sports may specify more specific dimensions in this range for regulation compliant billiard balls. For example, the World Pool-Billiard Association (WPA) specifies that a billiard ball for the game of pool has a diameter of 2.25 in. (57.15 mm), plus or minus 0.005 in. (0.127 mm). Also, in snooker, billiard balls may be 2 and 1/16 inches (52.5 mm) in diameter.
Billiard sports are played on a billiard table which has a rectangular horizontal planar surface called a bed that is bounded on four sides by cushions mounted along rails. The bed is often comprised of a cloth covered slate and the cushions are often comprised of a cloth covered rubber. The dimensions of a billiard table vary widely. For example, common pool tables have lengths that are 9-foot (2.7 m), 8 ft (2.4 m), or 7 ft (2.1 m) with a length to width radio of 2:1. The bed playing surface between the cushions and rails of a 9 foot (2.7 m) table, for example, may be 100 inches (254 cm) by 50 inches (127 cm). Also, for example, a snooker table may have dimensions of 11 feet 8.5 inches (356.9 cm) by 5 feet 10 inches (177.8 cm). It should also be appreciated that billiard tables for pool and snooker may include pockets for receiving billiard balls, whereas billiard tables for Carom billiards tables do not have pockets.
Billiard sports may benefit from improvements.